~Suzhou Pharma Small Class~
At present, the importance of laboratory biosafety has been paid more and more attention. Among them, the most important measures to ensure the biosafety of the laboratory are the use of biosafety cabinets, ultra-clean workbenches, fume hoods and other equipment. However, laboratory staff are not very clear about their performance, selection, operation and disadvantages, and sometimes may confuse biosafety cabinets, ultra-clean workbenches and fume hoods. In fact, there are essential differences among the three.
1. Different definitions
Biosafety cabinet (BSC): is a box-type air purification negative pressure safety device to prevent infectious experimental materials from polluting or infecting the laboratory or experimental operators in the process of experimental operation. It is used to protect staff, laboratory environment and experimental products, and is the most basic safety protection equipment in the biosafety protection barrier. It can be divided into 1-3 levels.
Fume hood: is also called fume hood. It is used to discharge toxic and harmful gases (toxic smoke or corrosive chemical gases) during the experimental operation to the outside to protect laboratory personnel from toxic chemical gases, and also to prevent powder inhalation hazards.
Ultra-clean worktable: It is designed to protect the experimental objects and materials operated in the worktable from pollution, and does not protect the staff and laboratory.
2. Different working principles
The working principle of the biosafety cabinet is to pump the air in the cabinet outward to keep the negative pressure in the cabinet and protect the staff through the vertical air flow; The outside air enters the safety cabinet after being filtered by HEPA filter to avoid contamination of the treated sample; The air in the cabinet also needs to be filtered by HEPA filter before being discharged into the atmosphere to protect the environment. At the same time, the external exhaust flow is also purified to prevent environmental pollution.
The working principle of the ultra-clean worktable is to blow the air outside the cabinet inward to keep the cabinet in a positive pressure state, and the air flow inside the cabinet is blown from top to bottom (also horizontal flow) to protect the experimental materials; The outside air enters the ultra-clean workbench after being filtered by the high-efficiency air filter, forming a continuous dust-free and sterile ultra-clean air laminar flow (more than 0.3 is removed μ M dust, fungi and bacterial spores). Ensure that the experimental object is not contaminated during operation.
The working principle of the fume hood: it is mainly to pump the air in the cabinet outward (without HEPA filter) to maintain the negative pressure in the cabinet, so that some toxic smoke and chemical gases in the experiment can be discharged in time, thus protecting the laboratory personnel and the environment.
3. Different protection objects
The biological safety cabinet protects the laboratory and experimental operators.
The fume hood protects the laboratory and experimental operators, and does not protect the experimental objects.
The protection object of the ultra-clean workbench is the experimental object, and the operator is not protected.
4. The pressure in the cabinet is different
Biosafety cabinet: negative pressure.
Ultra-clean workbench: positive pressure.
Ventilation cabinet: negative pressure.
5. The air flow direction in the cabinet is different
Biosafety cabinet: from the outside to the inside, from the bottom to the top.
Ultra-clean workbench: blow from inside to outside and from top to bottom (also horizontal flow).
Ventilation cabinet: from the outside to the inside, from the bottom to the top.
6. Different disadvantages
Ultra-clean worktable: protect samples, not people and laboratories. Once microbial samples are placed in the working area, laminar air will blow the air with microbial media to the front desk staff and laboratories, causing danger.
Fume hood: It can not effectively remove microbial media. Some microbial samples placed in the fume hood may spread outside the fume hood and pollute the laboratory environment.
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